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transmission/libtransmission/tracker.c

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/*
* This file Copyright (C) 2007 Charles Kerr <charles@rebelbase.com>
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#include <assert.h>
#include <ctype.h> /* isalnum */
#include <stdio.h> /* snprintf */
#include <stdlib.h>
#include <string.h> /* strcmp, strchr */
#include <libgen.h> /* basename */
#include <sys/queue.h> /* evhttp.h needs this */
#include <event.h>
#include <evhttp.h>
#include "transmission.h"
#include "bencode.h"
#include "completion.h"
#include "list.h"
#include "net.h"
#include "publish.h"
#include "shared.h"
#include "tracker.h"
#include "trevent.h"
#include "utils.h"
enum
{
/* seconds between tracker pulses */
PULSE_INTERVAL_MSEC = 1000,
/* maximum number of concurrent tracker socket connections */
MAX_TRACKER_SOCKETS = 16,
/* maximum number of concurrent tracker socket connections during shutdown.
* all the peer connections should be gone by now, so we can hog more
* connections to send `stop' messages to the trackers */
MAX_TRACKER_SOCKETS_DURING_SHUTDOWN = 64,
/* unless the tracker says otherwise, rescrape this frequently */
DEFAULT_SCRAPE_INTERVAL_SEC = (60 * 15),
/* unless the tracker says otherwise, this is the announce interval */
DEFAULT_ANNOUNCE_INTERVAL_SEC = (60 * 4),
/* unless the tracker says otherwise, this is the announce min_interval */
DEFAULT_ANNOUNCE_MIN_INTERVAL_SEC = (60 * 2),
/* this is how long we'll leave a request hanging before timeout */
TIMEOUT_INTERVAL_SEC = 45,
/* this is how long we'll leave a 'stop' request hanging before timeout.
we wait less time for this so it doesn't slow down shutdowns */
STOP_TIMEOUT_INTERVAL_SEC = 5,
/* the value of the 'numwant' argument passed in tracker requests. */
NUMWANT = 200,
/* the length of the 'key' argument passed in tracker requests */
KEYLEN = 10
};
/**
***
**/
struct tr_tracker
{
tr_handle * handle;
/* these are set from the latest scrape or tracker response */
int announceIntervalSec;
int announceMinIntervalSec;
int scrapeIntervalSec;
tr_tracker_info * redirect;
tr_tracker_info * addresses;
int addressIndex;
int addressCount;
int * tierFronts;
/* sent as the "key" argument in tracker requests
to verify us if our IP address changes.
This is immutable for the life of the tracker object. */
char key_param[KEYLEN+1];
tr_publisher_t * publisher;
/* torrent hash string */
uint8_t hash[SHA_DIGEST_LENGTH];
char escaped[SHA_DIGEST_LENGTH * 3 + 1];
char * name;
/* corresponds to the peer_id sent as a tracker request parameter.
one tracker admin says: "When the same torrent is opened and
closed and opened again without quitting Transmission ...
change the peerid. It would help sometimes if a stopped event
was missed to ensure that we didn't think someone was cheating. */
char peer_id[TR_ID_LEN + 1];
/* these are set from the latest tracker response... -1 is 'unknown' */
int timesDownloaded;
int seederCount;
int leecherCount;
char * trackerID;
time_t manualAnnounceAllowedAt;
time_t reannounceAt;
time_t scrapeAt;
unsigned int isRunning : 1;
};
/**
***
**/
static void
myDebug( const char * file, int line, const tr_tracker * t, const char * fmt, ... )
{
FILE * fp = tr_getLog( );
if( fp != NULL )
{
va_list args;
char timestr[64];
struct evbuffer * buf = evbuffer_new( );
char * myfile = tr_strdup( file );
evbuffer_add_printf( buf, "[%s] ", tr_getLogTimeStr( timestr, sizeof(timestr) ) );
if( t != NULL )
evbuffer_add_printf( buf, "%s ", t->name );
va_start( args, fmt );
evbuffer_add_vprintf( buf, fmt, args );
va_end( args );
evbuffer_add_printf( buf, " (%s:%d)\n", basename(myfile), line );
fwrite( EVBUFFER_DATA(buf), 1, EVBUFFER_LENGTH(buf), fp );
tr_free( myfile );
evbuffer_free( buf );
}
}
#define dbgmsg(t, fmt...) myDebug(__FILE__, __LINE__, t, ##fmt )
/***
****
***/
static tr_tracker_info *
getCurrentAddress( const tr_tracker * t )
{
assert( t->addresses != NULL );
assert( t->addressIndex >= 0 );
assert( t->addressIndex < t->addressCount );
return t->redirect ? t->redirect
: t->addresses + t->addressIndex;
}
static int
trackerSupportsScrape( const tr_tracker * t )
{
const tr_tracker_info * info = getCurrentAddress( t );
return ( info != NULL )
&& ( info->scrape != NULL )
&& ( info->scrape[0] != '\0' );
}
/***
****
***/
struct torrent_hash
{
tr_handle * handle;
uint8_t hash[SHA_DIGEST_LENGTH];
};
static struct torrent_hash*
torrentHashNew( tr_handle * handle, const tr_tracker * t )
{
struct torrent_hash * data = tr_new( struct torrent_hash, 1 );
data->handle = handle;
memcpy( data->hash, t->hash, SHA_DIGEST_LENGTH );
return data;
}
tr_tracker *
findTrackerFromHash( struct torrent_hash * data )
{
tr_torrent * torrent = tr_torrentFindFromHash( data->handle, data->hash );
return torrent ? torrent->tracker : NULL;
}
tr_tracker *
findTracker( tr_handle * handle, const uint8_t * hash )
{
tr_torrent * torrent = tr_torrentFindFromHash( handle, hash );
return torrent ? torrent->tracker : NULL;
}
/***
**** PUBLISH
***/
static const tr_tracker_event emptyEvent = { 0, NULL, NULL, NULL, 0 };
static void
publishMessage( tr_tracker * t, const char * msg, int type )
{
if( t != NULL )
{
tr_tracker_event event = emptyEvent;
event.hash = t->hash;
event.messageType = type;
event.text = msg;
tr_publisherPublish( t->publisher, t, &event );
}
}
static void
publishErrorClear( tr_tracker * t )
{
publishMessage( t, NULL, TR_TRACKER_ERROR_CLEAR );
}
static void
publishErrorMessageAndStop( tr_tracker * t, const char * msg )
{
t->isRunning = 0;
publishMessage( t, msg, TR_TRACKER_ERROR );
}
static void
publishWarning( tr_tracker * t, const char * msg )
{
publishMessage( t, msg, TR_TRACKER_WARNING );
}
static void
publishNewPeers( tr_tracker * t, int count, uint8_t * peers )
{
tr_tracker_event event = emptyEvent;
event.hash = t->hash;
event.messageType = TR_TRACKER_PEERS;
event.peerCount = count;
event.peerCompact = peers;
tr_inf( "Torrent \"%s\" got %d new peers", t->name, count );
tr_publisherPublish( t->publisher, t, &event );
}
/***
****
***/
static void onReqDone( tr_handle * handle );
static void
onStoppedResponse( struct evhttp_request * req UNUSED, void * handle )
{
dbgmsg( NULL, "got a response to some `stop' message" );
onReqDone( handle );
}
static int
parseBencResponse( struct evhttp_request * req, benc_val_t * setme )
{
const unsigned char * body = EVBUFFER_DATA( req->input_buffer );
const int bodylen = EVBUFFER_LENGTH( req->input_buffer );
int ret = 1;
int i;
for( i=0; ret && i<bodylen; ++i )
if( !tr_bencLoad( body+i, bodylen-1, setme, NULL ) )
ret = 0;
return ret;
}
static const char*
updateAddresses( tr_tracker * t, const struct evhttp_request * req )
{
const char * ret = NULL;
int moveToNextAddress = FALSE;
if( !req )
{
ret = "Tracker hasn't responded yet. Retrying...";
tr_inf( ret );
moveToNextAddress = TRUE;
}
else if( req->response_code == HTTP_OK )
{
if( t->redirect != NULL )
{
/* multitracker spec: "if a connection with a tracker is
successful, it will be moved to the front of the tier." */
const int i = t->addressIndex;
const int j = t->tierFronts[i];
const tr_tracker_info swap = t->addresses[i];
t->addresses[i] = t->addresses[j];
t->addresses[j] = swap;
}
}
else if( ( req->response_code == HTTP_MOVEPERM )
|| ( req->response_code == HTTP_MOVETEMP ) )
{
const char * loc = evhttp_find_header( req->input_headers, "Location" );
tr_tracker_info tmp;
if( tr_trackerInfoInit( &tmp, loc, -1 ) ) /* a bad redirect? */
{
moveToNextAddress = TRUE;
}
else if( req->response_code == HTTP_MOVEPERM )
{
tr_tracker_info * cur = &t->addresses[t->addressIndex];
tr_trackerInfoClear( cur );
*cur = tmp;
}
else if( req->response_code == HTTP_MOVETEMP )
{
if( t->redirect == NULL )
t->redirect = tr_new0( tr_tracker_info, 1 );
else
tr_trackerInfoClear( t->redirect );
*t->redirect = tmp;
}
}
else
{
moveToNextAddress = TRUE;
}
if( moveToNextAddress )
if ( ++t->addressIndex >= t->addressCount )
t->addressIndex = 0;
return ret;
}
/* Convert to compact form */
static uint8_t *
parseOldPeers( benc_val_t * bePeers, int * setmePeerCount )
{
int i;
uint8_t *compact, *walk;
const int peerCount = bePeers->val.l.count;
assert( bePeers->type == TYPE_LIST );
compact = tr_new( uint8_t, peerCount*6 );
for( i=0, walk=compact; i<peerCount; ++i )
{
struct in_addr addr;
tr_port_t port;
benc_val_t * val;
benc_val_t * peer = &bePeers->val.l.vals[i];
val = tr_bencDictFind( peer, "ip" );
if( !val || val->type!=TYPE_STR || tr_netResolve(val->val.s.s, &addr) )
continue;
memcpy( walk, &addr, 4 );
walk += 4;
val = tr_bencDictFind( peer, "port" );
if( !val || val->type!=TYPE_INT || val->val.i<0 || val->val.i>0xffff )
continue;
port = htons( val->val.i );
memcpy( walk, &port, 2 );
walk += 2;
}
*setmePeerCount = peerCount;
return compact;
}
static void
onTrackerResponse( struct evhttp_request * req, void * vhash )
{
const char * warning;
int responseCode;
struct torrent_hash * torrent_hash = (struct torrent_hash*) vhash;
tr_tracker * t = findTrackerFromHash( torrent_hash );
onReqDone( torrent_hash->handle );
tr_free( torrent_hash );
if( t == NULL ) /* tracker has been closed */
return;
dbgmsg( t, "got response from tracker: \"%s\"",
( req && req->response_code_line ) ? req->response_code_line
: "(null)" );
tr_inf( "Torrent \"%s\" tracker response: %s",
t->name,
( req ? req->response_code_line : "(null)") );
if( req && ( req->response_code == HTTP_OK ) )
{
benc_val_t benc;
const int bencLoaded = !parseBencResponse( req, &benc );
publishErrorClear( t );
if( bencLoaded && benc.type==TYPE_DICT )
{
benc_val_t * tmp;
if(( tmp = tr_bencDictFind( &benc, "failure reason" ))) {
dbgmsg( t, "got failure message [%s]", tmp->val.s.s );
publishErrorMessageAndStop( t, tmp->val.s.s );
}
if(( tmp = tr_bencDictFind( &benc, "warning message" ))) {
dbgmsg( t, "got warning message [%s]", tmp->val.s.s );
publishWarning( t, tmp->val.s.s );
}
if(( tmp = tr_bencDictFind( &benc, "interval" ))) {
dbgmsg( t, "setting interval to %d", tmp->val.i );
t->announceIntervalSec = tmp->val.i;
}
if(( tmp = tr_bencDictFind( &benc, "min interval" ))) {
dbgmsg( t, "setting min interval to %d", tmp->val.i );
t->announceMinIntervalSec = tmp->val.i;
}
if(( tmp = tr_bencDictFind( &benc, "tracker id" )))
t->trackerID = tr_strndup( tmp->val.s.s, tmp->val.s.i );
if(( tmp = tr_bencDictFind( &benc, "complete" )))
t->seederCount = tmp->val.i;
if(( tmp = tr_bencDictFind( &benc, "incomplete" )))
t->leecherCount = tmp->val.i;
if(( tmp = tr_bencDictFind( &benc, "peers" )))
{
int peerCount = 0;
uint8_t * peerCompact = NULL;
if( tmp->type == TYPE_LIST ) /* original protocol */
{
if( tmp->val.l.count > 0 )
peerCompact = parseOldPeers( tmp, &peerCount );
}
else if( tmp->type == TYPE_STR ) /* "compact" extension */
{
if( tmp->val.s.i >= 6 )
{
peerCount = tmp->val.s.i / 6;
peerCompact = tr_new( uint8_t, tmp->val.s.i );
memcpy( peerCompact, tmp->val.s.s, tmp->val.s.i );
}
}
publishNewPeers( t, peerCount, peerCompact );
tr_free( peerCompact );
}
}
if( bencLoaded )
tr_bencFree( &benc );
}
if (( warning = updateAddresses( t, req ) )) {
publishWarning( t, warning );
tr_err( warning );
}
/**
***
**/
responseCode = req ? req->response_code : 503;
if( 200<=responseCode && responseCode<=299 )
{
dbgmsg( t, "request succeeded. reannouncing in %d seconds",
t->announceIntervalSec );
t->reannounceAt = time(NULL) + t->announceIntervalSec;
t->manualAnnounceAllowedAt = time(NULL) + t->announceMinIntervalSec;
}
else if( 300<=responseCode && responseCode<=399 )
{
dbgmsg( t, "got a redirect; retrying immediately" );
/* it's a redirect... updateAddresses() has already
* parsed the redirect, all that's left is to retry */
t->reannounceAt = time(NULL);
t->manualAnnounceAllowedAt = time(NULL) + t->announceMinIntervalSec;
}
else if( 400<=responseCode && responseCode<=499 )
{
const char * err = req && req->response_code_line
? req->response_code_line
: "Unspecified 4xx error from tracker.";
dbgmsg( t, err );
/* The request could not be understood by the server due to
* malformed syntax. The client SHOULD NOT repeat the
* request without modifications. */
publishErrorMessageAndStop( t, err );
t->manualAnnounceAllowedAt = ~(time_t)0;
t->reannounceAt = 0;
}
else if( 500<=responseCode && responseCode<=599 )
{
dbgmsg( t, "Got a 5xx error... retrying in 15 seconds." );
/* Response status codes beginning with the digit "5" indicate
* cases in which the server is aware that it has erred or is
* incapable of performing the request. So we pause a bit and
* try again. */
if( req && req->response_code_line )
publishWarning( t, req->response_code_line );
t->manualAnnounceAllowedAt = ~(time_t)0;
t->reannounceAt = time(NULL) + 15;
}
else
{
dbgmsg( t, "Invalid response from tracker... retrying in 60 seconds." );
/* WTF did we get?? */
if( req && req->response_code_line )
publishWarning( t, req->response_code_line );
t->manualAnnounceAllowedAt = ~(time_t)0;
t->reannounceAt = time(NULL) + 60;
}
}
static void
onScrapeResponse( struct evhttp_request * req, void * vhash )
{
const char * warning;
time_t nextScrapeSec = 60;
struct torrent_hash * torrent_hash = (struct torrent_hash*) vhash;
tr_tracker * t = findTrackerFromHash( torrent_hash );
onReqDone( torrent_hash->handle );
tr_free( torrent_hash );
dbgmsg( t, "Got scrape response for '%s': %s (%d)", (t ? t->name : "(null)"), (req ? req->response_code_line : "(no line)"), (req ? req->response_code : -1) );
if( t == NULL ) /* tracker's been closed... */
return;
tr_inf( "Got scrape response for '%s': %s",
t->name,
( ( req && req->response_code_line ) ? req->response_code_line
: "(null)") );
if( req && ( req->response_code == HTTP_OK ) )
{
benc_val_t benc, *files;
const int bencLoaded = !parseBencResponse( req, &benc );
if( bencLoaded
&& (( files = tr_bencDictFind( &benc, "files" ) ))
&& ( files->type == TYPE_DICT ) )
{
int i;
for( i=0; i<files->val.l.count; i+=2 )
{
const uint8_t* hash =
(const uint8_t*) files->val.l.vals[i].val.s.s;
benc_val_t *tmp, *flags;
benc_val_t *tordict = &files->val.l.vals[i+1];
if( memcmp( t->hash, hash, SHA_DIGEST_LENGTH ) )
continue;
publishErrorClear( t );
if(( tmp = tr_bencDictFind( tordict, "complete" )))
t->seederCount = tmp->val.i;
if(( tmp = tr_bencDictFind( tordict, "incomplete" )))
t->leecherCount = tmp->val.i;
if(( tmp = tr_bencDictFind( tordict, "downloaded" )))
t->timesDownloaded = tmp->val.i;
if(( flags = tr_bencDictFind( tordict, "flags" )))
if(( tmp = tr_bencDictFind( flags, "min_request_interval")))
t->scrapeIntervalSec = tmp->val.i;
tr_dbg( "Torrent '%s' scrape successful."
" Rescraping in %d seconds",
t->name, t->scrapeIntervalSec );
nextScrapeSec = t->scrapeIntervalSec;
}
}
if( bencLoaded )
tr_bencFree( &benc );
}
if (( warning = updateAddresses( t, req ) )) {
tr_err( warning );
publishWarning( t, warning );
}
t->scrapeAt = time(NULL) + nextScrapeSec;
}
/***
****
***/
enum
{
TR_REQ_STARTED,
TR_REQ_COMPLETED,
TR_REQ_STOPPED,
TR_REQ_REANNOUNCE,
TR_REQ_SCRAPE,
TR_REQ_COUNT
};
struct tr_tracker_request
{
int port;
int timeout;
int reqtype; /* TR_REQ_* */
char * address;
char * uri;
struct evhttp_request * req;
uint8_t torrent_hash[SHA_DIGEST_LENGTH];
};
static void
freeRequest( struct tr_tracker_request * req )
{
tr_free( req->address );
tr_free( req->uri );
tr_free( req );
}
static void
addCommonHeaders( const tr_tracker * t,
struct evhttp_request * req )
{
char buf[1024];
const tr_tracker_info * address = getCurrentAddress( t );
snprintf( buf, sizeof(buf), "%s:%d", address->address, address->port );
evhttp_add_header( req->output_headers, "Host", buf );
evhttp_add_header( req->output_headers, "Connection", "close" );
evhttp_add_header( req->output_headers, "Content-Length", "0" );
evhttp_add_header( req->output_headers, "User-Agent",
TR_NAME "/" LONG_VERSION_STRING );
}
static char*
buildTrackerRequestURI( const tr_tracker * t,
const tr_torrent * torrent,
const char * eventName )
{
const int isStopping = !strcmp( eventName, "stopped" );
const int numwant = isStopping ? 0 : NUMWANT;
struct evbuffer * buf = evbuffer_new( );
char * ret;
char * ann = getCurrentAddress(t)->announce;
evbuffer_add_printf( buf, "%s"
"%cinfo_hash=%s"
"&peer_id=%s"
"&port=%d"
"&uploaded=%"PRIu64
"&downloaded=%"PRIu64
"&corrupt=%"PRIu64
"&left=%"PRIu64
"&compact=1"
"&numwant=%d"
"&key=%s"
"&supportcrypto=1"
"&requirecrypto=%d"
"%s%s"
"%s%s",
ann,
strchr(ann, '?') ? '&' : '?',
t->escaped,
t->peer_id,
tr_sharedGetPublicPort( t->handle->shared ),
torrent->uploadedCur,
torrent->downloadedCur,
torrent->corruptCur,
tr_cpLeftUntilComplete( torrent->completion ),
numwant,
t->key_param,
( t->handle->encryptionMode==TR_ENCRYPTION_REQUIRED ? 1 : 0 ),
( ( eventName && *eventName ) ? "&event=" : "" ),
( ( eventName && *eventName ) ? eventName : "" ),
( ( t->trackerID && *t->trackerID ) ? "&trackerid=" : "" ),
( ( t->trackerID && *t->trackerID ) ? t->trackerID : "" ) );
ret = tr_strdup( (char*) EVBUFFER_DATA( buf ) );
evbuffer_free( buf );
return ret;
}
static struct tr_tracker_request*
createRequest( tr_handle * handle, const tr_tracker * tracker, int reqtype )
{
static const char* strings[TR_REQ_COUNT] = { "started", "completed", "stopped", "", "err" };
const tr_torrent * torrent = tr_torrentFindFromHash( handle, tracker->hash );
const tr_tracker_info * address = getCurrentAddress( tracker );
const int isStopping = reqtype == TR_REQ_STOPPED;
const char * eventName = strings[reqtype];
struct tr_tracker_request * req;
req = tr_new0( struct tr_tracker_request, 1 );
req->address = tr_strdup( address->address );
req->port = address->port;
req->uri = buildTrackerRequestURI( tracker, torrent, eventName );
req->timeout = isStopping ? STOP_TIMEOUT_INTERVAL_SEC : TIMEOUT_INTERVAL_SEC;
req->reqtype = reqtype;
req->req = isStopping
? evhttp_request_new( onStoppedResponse, handle )
: evhttp_request_new( onTrackerResponse, torrentHashNew(handle, tracker) );
memcpy( req->torrent_hash, tracker->hash, SHA_DIGEST_LENGTH );
addCommonHeaders( tracker, req->req );
return req;
}
static struct tr_tracker_request*
createScrape( tr_handle * handle, const tr_tracker * tracker )
{
const tr_tracker_info * a = getCurrentAddress( tracker );
struct tr_tracker_request * req;
req = tr_new0( struct tr_tracker_request, 1 );
req->address = tr_strdup( a->address );
req->port = a->port;
req->timeout = TIMEOUT_INTERVAL_SEC;
req->req = evhttp_request_new( onScrapeResponse, torrentHashNew( handle, tracker ) );
req->reqtype = TR_REQ_SCRAPE;
tr_asprintf( &req->uri, "%s%cinfo_hash=%s", a->scrape, strchr(a->scrape,'?')?'&':'?', tracker->escaped );
memcpy( req->torrent_hash, tracker->hash, SHA_DIGEST_LENGTH );
addCommonHeaders( tracker, req->req );
return req;
}
struct tr_tracker_handle
{
int socketCount;
unsigned int isShuttingDown : 1;
tr_timer * pulseTimer;
tr_list * requestQueue;
tr_list * scrapeQueue;
};
static int pulse( void * vhandle );
static void
ensureGlobalsExist( tr_handle * handle )
{
if( handle->tracker == NULL )
{
handle->tracker = tr_new0( struct tr_tracker_handle, 1 );
handle->tracker->pulseTimer = tr_timerNew( handle, pulse, handle, PULSE_INTERVAL_MSEC );
dbgmsg( NULL, "creating tracker timer" );
}
}
static void
freeRequest2( void * req )
{
freeRequest( req );
}
void
tr_trackerShuttingDown( tr_handle * handle )
{
if( handle->tracker )
{
/* since we're shutting down, we don't need to scrape anymore... */
tr_list_free( &handle->tracker->scrapeQueue, freeRequest2 );
handle->tracker->isShuttingDown = 1;
}
}
static int
maybeFreeGlobals( tr_handle * handle )
{
int globalsExist = handle->tracker != NULL;
if( globalsExist
&& ( handle->tracker->socketCount < 1 )
&& ( handle->tracker->requestQueue == NULL )
&& ( handle->tracker->scrapeQueue == NULL )
&& ( handle->torrentList== NULL ) )
{
dbgmsg( NULL, "freeing tracker timer" );
tr_timerFree( &handle->tracker->pulseTimer );
tr_free( handle->tracker );
handle->tracker = NULL;
globalsExist = FALSE;
}
return globalsExist;
}
/***
****
***/
static int
freeConnection( void * evcon )
{
evhttp_connection_free( evcon );
return FALSE;
}
static void
connectionClosedCB( struct evhttp_connection * evcon, void * vhandle )
{
tr_handle * handle = vhandle;
/* libevent references evcon right after calling this function,
so we can't free it yet... defer it to after this call chain
has played out */
tr_timerNew( handle, freeConnection, evcon, 100 );
}
static struct evhttp_connection*
getConnection( tr_handle * handle, const char * address, int port )
{
struct evhttp_connection * c = evhttp_connection_new( address, port );
evhttp_connection_set_closecb( c, connectionClosedCB, handle );
return c;
}
static void
invokeRequest( tr_handle * handle, const struct tr_tracker_request * req )
{
struct evhttp_connection * evcon = getConnection( handle, req->address, req->port );
tr_tracker * t = findTracker( handle, req->torrent_hash );
dbgmsg( t, "sending '%s' to tracker %s:%d, timeout is %d", req->uri, req->address, req->port, (int)req->timeout );
evhttp_connection_set_timeout( evcon, req->timeout );
if( evhttp_make_request( evcon, req->req, EVHTTP_REQ_GET, req->uri ))
publishErrorMessageAndStop( t, "Tracker could not be reached." );
else {
++handle->tracker->socketCount;
dbgmsg( t, "incremented socket count to %d", handle->tracker->socketCount );
}
}
static void
invokeNextInQueue( tr_handle * handle, tr_list ** list )
{
struct tr_tracker_request * req = tr_list_pop_front( list );
invokeRequest( handle, req );
freeRequest( req );
}
static int
socketIsAvailable( tr_handle * handle )
{
const int max = handle->tracker->isShuttingDown
? MAX_TRACKER_SOCKETS_DURING_SHUTDOWN
: MAX_TRACKER_SOCKETS;
return handle->tracker->socketCount < max;
}
static void ensureGlobalsExist( tr_handle * );
static void
enqueueScrape( tr_handle * handle, const tr_tracker * tracker )
{
struct tr_tracker_request * req;
ensureGlobalsExist( handle );
req = createScrape( handle, tracker );
tr_list_append( &handle->tracker->scrapeQueue, req );
}
static void
enqueueRequest( tr_handle * handle, const tr_tracker * tracker, int reqtype )
{
struct tr_tracker_request * req;
ensureGlobalsExist( handle );
req = createRequest( handle, tracker, reqtype );
tr_list_append( &handle->tracker->requestQueue, req );
}
static int
pulse( void * vhandle )
{
tr_handle * handle = vhandle;
struct tr_tracker_handle * th = handle->tracker;
tr_torrent * tor;
const time_t now = time( NULL );
if( handle->tracker == NULL )
return FALSE;
if( handle->tracker->socketCount || tr_list_size(th->requestQueue) || tr_list_size(th->scrapeQueue) )
dbgmsg( NULL, "tracker pulse... %d sockets, %d reqs left, %d scrapes left", handle->tracker->socketCount, tr_list_size(th->requestQueue), tr_list_size(th->scrapeQueue) );
/* upkeep: queue periodic rescrape / reannounce */
for( tor=handle->torrentList; tor; tor=tor->next )
{
tr_tracker * t = tor->tracker;
if( t->scrapeAt && trackerSupportsScrape( t ) && ( now >= t->scrapeAt ) ) {
t->scrapeAt = 0;
enqueueScrape( handle, t );
}
if( t->reannounceAt && t->isRunning && ( now >= t->reannounceAt ) ) {
t->reannounceAt = 0;
enqueueRequest( handle, t, TR_REQ_REANNOUNCE );
}
}
if( handle->tracker->socketCount || tr_list_size(th->requestQueue) || tr_list_size(th->scrapeQueue) )
dbgmsg( NULL, "tracker pulse after upkeep... %d sockets, %d reqs left, %d scrapes left", handle->tracker->socketCount, tr_list_size(th->requestQueue), tr_list_size(th->scrapeQueue) );
/* look for things to do... process all the requests, then process all the scrapes */
while( th->requestQueue && socketIsAvailable( handle ) )
invokeNextInQueue( handle, &th->requestQueue );
while( th->scrapeQueue && socketIsAvailable( handle ) )
invokeNextInQueue( handle, &th->scrapeQueue );
if( handle->tracker->socketCount || tr_list_size(th->requestQueue) || tr_list_size(th->scrapeQueue) )
dbgmsg( NULL, "tracker pulse done... %d sockets, %d reqs left, %d scrapes left", handle->tracker->socketCount, tr_list_size(th->requestQueue), tr_list_size(th->scrapeQueue) );
return maybeFreeGlobals( handle );
}
static void
onReqDone( tr_handle * handle )
{
if( handle->tracker )
{
pulse( handle );
--handle->tracker->socketCount;
dbgmsg( NULL, "decrementing socket count to %d", handle->tracker->socketCount );
}
}
/***
**** LIFE CYCLE
***/
static void
generateKeyParam( char * msg, int len )
{
int i;
const char * pool = "abcdefghijklmnopqrstuvwxyz0123456789";
const int poolSize = strlen( pool );
for( i=0; i<len; ++i )
*msg++ = pool[tr_rand(poolSize)];
*msg = '\0';
}
static void
escape( char * out, const uint8_t * in, int in_len ) /* rfc2396 */
{
const uint8_t *end = in + in_len;
while( in != end )
if( isalnum(*in) )
*out++ = (char) *in++;
else
out += snprintf( out, 4, "%%%02X", (unsigned int)*in++ );
*out = '\0';
}
tr_tracker *
tr_trackerNew( const tr_torrent * torrent )
{
const tr_info * info = &torrent->info;
int i, j, sum, *iwalk;
tr_tracker_info * nwalk;
tr_tracker * t;
t = tr_new0( tr_tracker, 1 );
t->handle = torrent->handle;
t->scrapeIntervalSec = DEFAULT_SCRAPE_INTERVAL_SEC;
t->announceIntervalSec = DEFAULT_ANNOUNCE_INTERVAL_SEC;
t->announceMinIntervalSec = DEFAULT_ANNOUNCE_MIN_INTERVAL_SEC;
generateKeyParam( t->key_param, KEYLEN );
t->publisher = tr_publisherNew( );
t->timesDownloaded = -1;
t->seederCount = -1;
t->leecherCount = -1;
t->manualAnnounceAllowedAt = ~(time_t)0;
t->name = tr_strdup( info->name );
memcpy( t->hash, info->hash, SHA_DIGEST_LENGTH );
escape( t->escaped, info->hash, SHA_DIGEST_LENGTH );
for( sum=i=0; i<info->trackerTiers; ++i )
sum += info->trackerList[i].count;
t->addresses = nwalk = tr_new0( tr_tracker_info, sum );
t->addressIndex = 0;
t->addressCount = sum;
t->tierFronts = iwalk = tr_new0( int, sum );
for( i=0; i<info->trackerTiers; ++i )
{
const int tierFront = nwalk - t->addresses;
for( j=0; j<info->trackerList[i].count; ++j )
{
const tr_tracker_info * src = &info->trackerList[i].list[j];
nwalk->address = tr_strdup( src->address );
nwalk->port = src->port;
nwalk->announce = tr_strdup( src->announce );
nwalk->scrape = tr_strdup( src->scrape );
++nwalk;
*iwalk++ = tierFront;
}
}
assert( nwalk - t->addresses == sum );
assert( iwalk - t->tierFronts == sum );
if( trackerSupportsScrape( t ) )
enqueueScrape( t->handle, t );
return t;
}
static void
onTrackerFreeNow( void * vt )
{
int i;
tr_tracker * t = vt;
tr_publisherFree( &t->publisher );
tr_free( t->name );
tr_free( t->trackerID );
/* addresses... */
for( i=0; i<t->addressCount; ++i )
tr_trackerInfoClear( &t->addresses[i] );
tr_free( t->addresses );
tr_free( t->tierFronts );
/* redirect... */
if( t->redirect ) {
tr_trackerInfoClear( t->redirect );
tr_free( t->redirect );
}
tr_free( t );
}
void
tr_trackerFree( tr_tracker * t )
{
tr_runInEventThread( t->handle, onTrackerFreeNow, t );
}
/***
**** PUBLIC
***/
tr_publisher_tag
tr_trackerSubscribe( tr_tracker * t,
tr_delivery_func func,
void * user_data )
{
return tr_publisherSubscribe( t->publisher, func, user_data );
}
void
tr_trackerUnsubscribe( tr_tracker * t,
tr_publisher_tag tag )
{
tr_publisherUnsubscribe( t->publisher, tag );
}
const tr_tracker_info *
tr_trackerGetAddress( const tr_tracker * t )
{
return getCurrentAddress( t );
}
int
tr_trackerCanManualAnnounce ( const tr_tracker * t)
{
return t->isRunning
&& ( time(NULL) >= t->manualAnnounceAllowedAt );
}
void
tr_trackerGetCounts( const tr_tracker * t,
int * setme_completedCount,
int * setme_leecherCount,
int * setme_seederCount )
{
if( setme_completedCount )
*setme_completedCount = t->timesDownloaded;
if( setme_leecherCount )
*setme_leecherCount = t->leecherCount;
if( setme_seederCount )
*setme_seederCount = t->seederCount;
}
void
tr_trackerStart( tr_tracker * t )
{
tr_peerIdNew( t->peer_id, sizeof(t->peer_id) );
if( t->isRunning == 0 ) {
t->isRunning = 1;
enqueueRequest( t->handle, t, TR_REQ_STARTED );
}
}
void
tr_trackerReannounce( tr_tracker * t )
{
enqueueRequest( t->handle, t, TR_REQ_REANNOUNCE );
}
void
tr_trackerCompleted( tr_tracker * t )
{
enqueueRequest( t->handle, t, TR_REQ_COMPLETED );
}
void
tr_trackerStop( tr_tracker * t )
{
if( t->isRunning ) {
t->isRunning = 0;
enqueueRequest( t->handle, t, TR_REQ_STOPPED );
}
}
void
tr_trackerChangeMyPort( tr_tracker * t )
{
if( t->isRunning )
tr_trackerReannounce( t );
}
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